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This is a hand drawn schematic of how to wire your speakers for a stereo or sound card. I use a 1/4 inch stereo phone plug because it's easy to work with. Then I get an adaptor from Radio Shack to adapt to the miniature 1/8 inch plug if I want to plug into a CD player or cassette.
You can use a "wall-wart" 12 or 24 volt transformer instead of the doorbell transformer shown. For a 12 volt transformer, use a # 1893 bulb, for a 24 volt transformer, use a # 1864 bulb.
Because most CD or Cassette players limit the volume to the headphone jack, the sound may not be very loud. The preferred connection is to wire a stereo jack directly to the 8 ohm speaker terminals on your stereo.
Shown above is the inside of a new RCA speaker showing the internal wiring. The black wire from the cord attaches to the left speaker terminal and the left terminal of the volume control. The center terminal of the volume control attaches to the right speaker terminal. The white wire from the cord attaches to the right terminal of the volume control.
This diagram below is for historical purposes only. It shows how the speakers were originally wired in a drive-in sound system.
The drive-in used a large tube type amplifier to provide about 1/2 to 1 watt of power to each speaker. The output was at a fairly high voltage, around 70 volts, and the transformer in the junction box stepped this down to the 8 ohm speaker impedance. When the drive-in had 500 or more spaces, multiple amplifiers were needed to drive the field of speakers.
Enjoy your speakers and keep the drive-in memories alive. If you still have a drive-in in your neighborhood, attend them often and enjoy movies under the stars on that giant screen.